package IO流;

import java.util.HashMap;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author:谢君臣
 * @Date:2021/5/22-10:41
 * @version:1.0
 * @function:
 */
public class HashMapTest {
    public static void main(String[] args) {
        HashMap map = new HashMap();
        map.put("sdf",1);
        System.out.println(map.containsKey(null));
        System.out.println(map.get("sdaf"));
        ConcurrentHashMap hashMap = new ConcurrentHashMap();
        hashMap.put("张三","25");

    }
}
